Extended-release naltrexone (XR-NTX, VIVITROL) is an FDA-approved medication with efficacy in treating alcohol dependence and prevention of relapse to opioid dependence. It has shown promise in reducing relapse to amphetamine use among amphetamine-dependent, yet currently amphetamine-abstinent heterosexuals. The investigators will expand upon this promising work to determine whether monthly intramuscular injections of naltrexone will reduce methamphetamine (meth) use among actively using, meth-dependent men who have sex with men (MSM) in this double-blind randomized controlled trial of extended-release naltrexone versus placebo. The investigators will focus on MSM because of the disproportionate and intertwining epidemics of meth use and HIV in this population.

The investigators will enroll 100 sexually active, meth-dependent MSM who will be randomized 1:1 to receive monthly injections of extended-release naltrexone (n=50) or placebo (n=50) for 12 weeks at weeks 0, 4, and 8. Study participants will be seen weekly at our site at the HIV Prevention Section of the San Francisco Department of Public Health, where they will provide urine for drug testing and participate in substance use counseling. All participants will receive HIV risk-reduction counseling. Behavior will be assessed using standardized measures via audio computer-assisted self-interview (ACASI).

Eligibility

Ages Eligible for Study:

18 Years to 65 Years

Genders Eligible for Study:

Male

Accepts Healthy Volunteers:

No

Criteria

Inclusion criteria:

born male; or born female and does not identify as female

reports having anal sex with men in the prior six months while under the influence of meth;

diagnosed with meth dependence as determined by SCID;

interested in stopping or reducing meth use;

at least one meth-positive urine during screening and run-in period;

no current acute illnesses requiring prolonged medical care;

no chronic illnesses that are likely to progress clinically during trial participation;

able and willing to provide informed consent and adhere to visit schedule;

age 18-65 years;

baseline CBC, total protein, albumin, glucose, alkaline phosphatase, creatinine, BUN, total bilirubin, and electrolytes without clinically significant abnormalities as determined by investigator in conjunction with symptoms, physical exam, and medical history.

Exclusion criteria:

any psychiatric condition (e.g. current depression with suicidal ideation or schizophrenia) that would preclude safe participation in the protocol;

known intolerance and/or hypersensitivity to naltrexone, carboxymethylcellulose, or polylactide-co-polymers (PLG) or any other components of the diluents;

current use of or dependence on any opioids; a known medical condition which currently requires or is likely to require opioid analgesics; or positive opioid urine screening tests

pending legal proceedings with high risk for incarceration during the time of planned study participation;

any condition that, in the principal investigator's judgment, interferes with safe study participation or adherence to study procedures.

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01449565